1. Field of the Invention
The present invention relates to a method and system for optical coherence tomography.
2. Description of the Related Art
Optical coherence tomography (OCT) is a non-invasive method of investigating the inside of light-scattering specimens. Due to its light-scattering properties biological tissue is particularly suitable for diagnostic examination by OCT. Since for OCT relatively low light intensities are sufficient and the wavelengths of the light used mostly come within the near infrared range (750 nm to 1350 nm), unlike ionizing X-ray diagnostics it does not contaminate biological tissue with radiation. It is therefore particularly significant for medicine. The currently most important areas of application of OCT are in ophthalmology, dermatology and the diagnosis of cancer. However, there are also some non-medical applications, such as, e.g., in materials testing.
OCT is roughly comparable to ultrasound diagnostics, wherein, instead of sound, broadband light of a very short coherence length is used. The running times of the light reflected on different boundary layers within the specimen are recorded by an interferometer. With OCT typical resolutions higher by one or two orders of magnitude can be achieved than with ultrasound, but the measuring depth achievable is considerably smaller. Due to optical scattering the cross-section images obtained only reach into the tissue up to a depth of a few millimeters.